Oidium of grapes: a description of the disease and measures to combat powdery mildew

One of the main problems that summer residents who grow grapes face almost every year is powdery mildew or powdery mildew. This harmful disease of grapes is widespread in all countries with developed viticulture, as a rule, in zones with dry and hot summers. However, grapes can be saved.

You will learn how to completely suppress powdery mildew in early spring so that in the fall the annual vine is free from infection even in the most susceptible grape varieties, you will learn from our article.

Powdery mildew signs: how powdery mildew manifests itself on grapes

Powdery mildew (powdery mildew), its causative agent is the erysiphoid mushroom (Uncinula necator = Oidium tuckeri)that lives on the surface of shoots, leaves and berries.

Oidium on grapes usually starts to appear first. on leaves and young shoots (where he, in fact, hibernates) with top (front or outside) side of the sheet as powdery gray-white bloom (as if sprinkled with flour) that can be easily wiped off with your fingers.

By the way! And heremildew (downy mildew) always appears on the underside of leaves.

Already after flowering, when the fruits have set and they begin to ripen, a characteristic sign of the presence of powdery mildew on grapes is the fact that green berries are cracked (previously they are also covered with a white bloom). Thereby outward all their insides are turned inside out (seeds)that almost instantly start rot or dry out (depending on the weather)being affected by various bacteria and fungi (for example, gray mold), while highlighting the characteristic the smell of missing fish (rusty or rotten herring).

Dark, very quickly blackening spots appear on the shoots. This vine does not ripen for a long time and freezes very easily in winter.

The main danger of this fungal disease is that, appearing on grapes, it strikes it suddenly, and you can lose most of the harvest in a couple of weeks, which will simply be lost.

Important! All affected brushes must be cut off and thrown away (buried), and not in a compost pit, otherwise the fungus will return again.

The main reason provoking grape disease oidium (powdery mildew), more precisely, the most favorable conditions for development are - dry and hot weather without rainas well as constanttemperature changes (it's cold enough at night, very hot during the day).

It is worth distinguishing! But, on the contrary, wet weather Is the main reason for development mildew (downy mildew).

Video: description of the disease and measures to combat powdery mildew on grapes

The best prevention of oidium is proper grape care

So that the grapes do not get sick and do not have to be treated for oidium, the plant should not suffer from lack of moisture (that is, you need grapes water properly), it is also recommended feed regularly and abundantly (especially potassium and calcium).

Can't be allowed so that grape bushesespecially after cold rains, in the heat of the day stood damp. They must be well ventilated, that is plantings should not be thickened, in other words, a regular summer pruning, namely pinching, chasing and pinching, while you also need to remove unnecessary leaves in the area of ​​the bunches.

Note! The best thing tie grapes to trellises... How to do it correctly, read in this article.

But the most effective way to prevent powdery mildew on grapes is to grow varieties that are most resistant (less susceptible) to this disease.

So, the following grape varieties are considered the most resistant to powdery mildew: Red, Ainset, Rylines, Friendship, Bianca, Ruby Magaracha, Saperavi Dediani, Zhgia, Ruby, Frumoasa Albe, Srebrostruy, Liana, Delight.

Advice! You can try (unlikely, but you can try) to protect the grapes from mildew and oidium just by planting under a bush calendula, onion or garlic.

When to process grapes from powdery mildew powder: a protective spraying scheme

In order not to fight the powdery mildew directly, it is necessary to take timely preventive measures to protect the grapes from this fungal disease.

The main processing of grapes from oidium must be carried out before flowering:

1. The first treatment is carried out when 10-15 cm young shoots are formed on a grape bush, on which 3-4 leaves will appear. At this moment, it is optimal to use systemic drugs (Skor, Topsin-M, Strobi and many others (one to choose from).
2. The second treatment - a week and a half before flowering (during the budding period). It is necessary to repeat the spraying with the systemic fungicide (one of your choice).

As a rule, such spraying should be enough to protect the grapes, and this will be a guarantee that the powder will not manifest.

If for some reason you did not carry out the spring processing of the grapes before flowering, or it did not help you, and the grape bushes and bunches still became infected and turned white, then during the period of fruit formation (grape bunches) this process should be approached more carefully and carefully.

The point is that at this time undesirable (but possible, if necessary) the use of systemic chemical fungicides due to their rather long waiting period. Better to use sulfur-containing drugs and biological agentsthat have a minimum waiting time and are well washed off by rain.

Advice! In autumn, after harvest (after trimmingbut before shelter for the winter), should also eradication of grapesto try to get rid of the fungus, so that it does not stay overwintering on the bush and in the ground.

How and what to treat oidium on grapes: preparations for processing

It is very good if you notice white bloom on the leaves before flowering. But if you were not lucky and you found powdery mildew on the grapes already during its fruiting period, that is, after flowering, when the berries began to ripen, then you need to take the most urgent measures to combat it.

A few tips and tricks, the implementation of which will make your oidium treatment as effective as possible:

• Very important properly handle vines... Spray leaves and berries enough abundantlyso that the solution reaches the maximum area (from all sides).
• Fungicides (remedies for diseases) should alternate (i.e. use drugs with different active ingredients) so that addiction (resistance) does not occur and the effect of use is maximized.
• Treatments should be carried out at intervals of 7-14 days (more often with biological and contact preparations, and less often with chemical and systemic preparations).
• Be sure to pay attention to waiting period the drugs used, for example, "Quadris" - 25 days, and "Falcon" - from 30-40 days.

In this case, chemical fungicides based on triazoles and strobilurins can be used at least if at least 20-25 days left before ripening, and even better 30-40.

Accordingly, it is most reasonable to use such drugs before flowering.

Chemicals

To protect and combat this fungal disease of grapes, it is necessary to use the following chemicals against powdery mildew:

Sulfur products (based on colloidal sulfur):

• Colloidal sulfur (contact fungicide and acaricide);

• Tiovit Jet;
  
• Cumulus DF.

Colloidal sulfur is, perhaps, one of the safest and most effective drugs to combat the first signs of powdery mildew on grapes. Its waiting period is only 2-3 days.

Important! Processing sulfur-containing drugs should be carried out at a temperature not lower than +20 degrees (but not higher than +30).

The bottom line is that sulfur fights powdery mildew on grapes using the method fumes, therefore, there is a mandatory need for warm weather.

Also worth knowingthat spraying should be carried out either early in the morning, or late in the evening, or in cloudy weatherso that the bunches do not get burned in the scorching daytime sun.

It should also be borne in mind that the protection period for a grape bush treated with colloidal sulfur is only about 1-2 weeks. And since this is a contact preparation that is easily washed off, therefore, spraying is recommended to be repeated at least every 2 weeks, or earlier if it rains.

It is not difficult to prepare a working solution of colloidal sulfur, and it must be done correctly:

1. First, pour colloidal sulfur into a jar (consumption - 30-40 grams per 10 liters).
2. Gradually pouring water into the container, stir until a homogeneous mass (gruel) is obtained.
3. Then the resulting concentrated solution is poured into a bucket and stirred again.
4. Strain, pour into a sprayer, and then carry out a thorough treatment on the leaf and bunches.

Video: colloidal sulfur is a simple and reliable remedy for oidium on grapes

Important! Some, probably still inexperienced, growers somewhat erroneously advise in early spring, even on bare vine, to spray the grapes from the appearance of powdery mildew copper sulfate or Bordeaux liquid and other copper-based products.

Advice! Copper-containing preparations (copper sulfate, Bordeaux liquid, Abiga-Peak, Hom, Oksikhom, Kuprolux, Broneks, Ordan, Kurzat) are best dealt with not with oidium, but with mildew (downy mildew)and also with anthracnose and phomopsis (black spot).

Nevertheless, there is an opinion that such a thing can work against oidium. copper-containing agent (based on copper oxychloride) like Abiga-Peak (contact fungicide of protective action).

Interesting! In certain sources, it is recommended to use it to combat powdery mildew. inkstonerather than copper.

Preparations based on triazole (as well as morpholines (cinnamic acid derivatives):

• Speed ​​(Difenoconazole, systemic contact fungicide of protective-treating action);

Analogs preparations - Raek, Keeper, Pure color.

• Medea (Difenoconazole and Flutriafol, systemic contact fungicide of protective-treating action);

• Bayleton (Triadimefon (Bayleton), systemic fungicide of protective and healing action);

Analogs - Bizafon, Privent.

• Topaz (Penconazole (Topaz), systemic fungicide of protective action);

• Falcon (Spiroxamine, Tebuconazole and Triadimenol (Baytan), a systemic fungicide of protective and healing action);
• Wagon (Tebuconazole, a systemic fungicide of protective and healing action);
• Folicour (Tebuconazole, a systemic fungicide of protective and healing action);

Analogs - Kolosal, Ikarus, Tebuzol.

• Revus Top (Difenoconazole and Mandipropamide, systemic contact fungicide of protective-treating action);
• Tilt (Propiconazole, systemic fungicide of protective and curative action);

Analogs - Agrolekar, Forecast, Chistoflor.

• Title 390 (Propiconazole, systemic fungicide of protective and curative action);

If in the preparations Prognoz, Tilt, Chistoflor and Agrolekar 250 g / l Propiconazole, then in Title deeds -390.

• Alto Super (Propiconazole and Ciproconazole, systemic contact fungicide of protective-healing action);

Analogs - Zoltan, Virtuoso.

• Impact (Flutriafol, systemic fungicide of protective and curative action).

Analogs - Inplant, Triafol, Fitolekar, Flutrivit, Phoenix, Foris.

But the basis benzimidazoles:

• Topsin-M (Thiophanate methyl, systemic contact fungicide of protective action);

Analogs - Thiophene, Thioma.

• Fundazol (Benomil (Fundazol), systemic contact protective fungicide and insecticide).

Preparations based on strobilurins:

• Cabrio top (Pyraclostrobin + Metiram, contact fungicide of protective action);
• Collis (Boscalid + Kresoxim-methyl, systemic fungicide of protective-treating action);
• Bellis (Boscalid + Pyraclostrobin, systemic contact fungicide of protective action);
• Signum (Boscalid + Pyraclostrobin, systemic contact fungicide of protective action);
• Quadris (Azoxystrobin, systemic contact protective fungicide);

There is also Quadris Top (Azoxystrobin + Difenoconazole).

• Tersel (Dithianon and Pyraclostrobin, contact fungicide of protective and curative action);
• Strobe (Kresoxim-methyl, systemic fungicide of protective and curative action).

Analogs - Garden, Strobitek.

Based on other substances:

• Talendo (Proquinazide, contact fungicide of protective action);

Analog - Talius.

• Vivando (Metrafenone, a systemic protective fungicide).
• Moon Experience (Pyrimethanil and Fluopyram, a systemic fungicide of a curative action);
• Moon Tranquility (Pyrimethanil and Fluopyram,systemic fungicide of a curative action).

Biologicals

Recently, the use of all kinds of biological agents to fight diseases has become quite popular.

So, the following biological products can be used against powdery mildew on grapes:

• Alirin-B (Bacillus subtilis, strain B-10 VIZR, systemic contact fungicide of protective and therapeutic action);

• Baktofit (Bacillus subtilis strain IPM 215, contact fungicide of protective and therapeutic action);

• Baxis (Bacillus subtilis strain 63-Z, protective and curing fungicide);
• Vitaplan (Bacillus subtilis strain VKM-B-2604D and VKM-V-2605D, protective fungicide against mildew and oidium);
• Planriz (Pseudomonas fluorescens strain AP-33, contact fungicide);

• Rizoplan (Pseudomonas fluorescens strain AP-33, contact fungicide);

Planriz and Rizoplan are complete analogues.

• Sporobacterin (Bacillus subtilis and Trichoderma viride, strain 4097, systemic contact fungicide of protective and therapeutic action);

• Fitosporin (Bacillus subtilis strain 26 D, systemic fungicide of protective and curative action);

• Gaupsin (two strains of soil bacteria Pseudomonas aureofaciens, insectofungicide complex action).

Also, against oidium should be effective Pentaphagus, Trichophyte, Trichodermin and other drugs based on Bacillus subtilis (hay stick).

Folk remedies

To remove powdery mildew and at the same time not particularly think about the negative consequences during the fruiting period of grapes, it makes sense to try to turn to folk remedies.

However, it should be understood that the effectiveness of such funds is extremely low.

The essence of the applicationacidic (horsetail, whey) and alkaline (soda, wood ash) solutions in that neutral acidity is most favorable for the fungus, while an increase or decrease in acidity should cause its death.

Soda solution

A truly folk remedy in the fight against powdery mildew on grapes is to prepare a soda solution that can be used without fear. in the stage of ripening berries.

Recipe: 40-50 grams of soda ash per 10 liters of water + 40-50 grams of grated household or green soap can be added.

Important!Also, the solution will help protect the grapes from mildew (downy mildew) and anthracnose.

Wood ash

Another natural folk remedy for treating grapes from powdery mildew is wood ash.

To prepare an ash solution for processing grape bushes, you will need:

1. Pour 400 grams of ash into a bucket of water and stir well.
2. Let it brew for 1-2 days so that the ash extract is the most effective.
3. Add 3 tbsp. spoons (40-50 grams) of laundry soap or green soap (for better adhesion).
4. Strain, pour into a sprayer and process.

By the way! Wood ash - it is also an excellent potash fertilizer, that is, it is an excellent foliar feeding.

Video: wood ash - a miracle remedy for powdery mildew on grapes

Whey, sour milk and other acidic products

Another safe way to control powdery mildew on grapes is to spray it with whey or sour milk.

Infusion horsetail... Recipe: Boil 100 grams of dry horsetail per 5 liters of water, let it brew for 12 hours, add 40-50 grams of laundry or green soap.

Infusion fermented sour bread... Recipe: 1 kg of dry crusts per 10 liters of water, 1-2 tbsp. tablespoons of sugar for better fermentation, let it brew for 3-5 days.

Mature hay

A full bucket of rotten hay is filled, filled with water and infused for about 4-7 days in a warm place. During this time, the mixture appears hay stick, which when spraying should "gobble up" the fungus, but first the infusion must be diluted with water in a ratio of 1 to 3.

Important! It should be understood that folk remedies are relatively weak remedies for the treatment of oidium, which are not suitable for the fight if the disease is raging in full force in the vineyard.

If you want to have a luxurious and high-quality grape harvest at the exit, you need to make every effort to protect it from powdery mildew. For this, it is imperative to use the most effective chemical and biological agents. The main thing is not to miss the beginning of the disease! And if you have not noticed the outbreak, continue to fight systematically and regularly, so to speak, to the bitter end.

Video: how to deal with powdery mildew (powdery mildew) on grapes

By the way! About, how and how to treat grapes from other diseases and pests in spring You can find out from this common stuff.